Key parameters at a glance

A radius of 2.17 Earth radii
A mass of 4.70 Earth masses
Surface gravity around 1.00 g
An orbital period of 16.146 days
Semi-major axis 0.1162 AU
Equilibrium temperature 590 K (317 °C)
Distance from Earth 351.58 light-years
Earth Similarity Index 0.442
Travel time at Voyager 1 speed 6,200,168 years
Almost certainly tidally locked to its host star given the close orbit

4 siblings around Kepler-102

Kepler-102 e shares its host star with 4 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-102 b	Rocky Terrestrial	0.46	1.10	5.287	857	2014
Kepler-102 c	Rocky Terrestrial	0.57	1.70	7.071	777	2014
Kepler-102 d	Rocky Terrestrial	1.15	3.00	10.312	686	2014
Kepler-102 e this	Sub-Neptune	2.17	4.70	16.146	590	2013
Kepler-102 f	Rocky Terrestrial	0.86	4.30	27.454	495	2014

Kepler-102 e Planet Profile

Physical Specs

Radius

2.17 R⊕

Radius (Jupiter)

0.194 R♃

Mass

4.70 M⊕

Mass (Jupiter)

0.015 M♃

Density

2.50 g/cm³

Surface Gravity

1.00 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.442

HZ Position Inner

Controversial No

Discovery

Year 2013

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1720of 1978

top 86.9%

This planet

2.17R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-1329 b 2.17 R⊕ Kepler-797 b 2.17 R⊕ Kepler-304 c 2.17 R⊕

Metric	Earth	Kepler-102 e	Jupiter
Radius (R⊕)	1.00	2.17	11.21
Mass (M⊕)	1.00	4.70	317.83
Density (g/cm³)	5.51	2.50	1.33
Surface Gravity (g)	1.00	1.00	2.53
Insolation (S⊕)	1.00	20.30	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	4.700 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	4.742 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 123357864

Gaia DR2

Gaia DR2 2119583201145735808

Gaia DR3

Gaia DR3 2119583201145735808

System

Kepler-102

Percentile among Sub-Neptune cohort

Radius 2.170 R⊕ · percentile 13 / cohort 1978

Mass 4.700 M⊕ · percentile 3 / cohort 1978

Orbital period 16.15 d · percentile 54 / cohort 1946

Distance 107.80 pc · percentile 21 / cohort 1975

ESI 0.442 · percentile 61 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

16.146 days

Semi-major axis

0.1162 AU

Eccentricity

0.089

Inclination

89.49 °

Year Length

A year here lasts approximately 16.15 Earth days (4.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1162 AU.

Transit Fingerprint

Depth

0.099 %

Duration

3.724 h

Impact parameter b

0.300

Rp / R★

0.031610

Transit midpoint (BJD)

2,454,967.7537

Photometric dip

Transit produces a flux drop of 989 ppm lasting ≈ 3.72 h.

Extended Orbital Architecture

Planet / star radius ratio

0.031610

Semi-major axis / stellar radius

21.600

Impact parameter (b)

0.300

RV semi-amplitude (K)

1.370 m/s

Transit mid-time (BJD)

2,454,967.7537

Angular separation (arcsec)

1.08000

Eq. Temperature

590K

(317 °C)

Insolation (S⊕)

20.30

Earth = 1.00

Earth Similarity (ESI)

0.442

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Wang et al. 2014

Instrument

Kepler CCD Array

Publication

2014-03

Observation locale

Space

Discovery cohort

Planets confirmed in 2013 at Kepler (12 shown).

Kepler-69 c · Super-Earth Kepler-61 b · Sub-Neptune Kepler-62 e · Super-Earth KOI-351 f · Sub-Neptune Kepler-62 f · Super-Earth KOI-351 e · Sub-Neptune Kepler-1704 b · Gas Giant Kepler-37 d · Sub-Neptune Kepler-282 e · Sub-Neptune KOI-351 h · Gas Giant KOI-351 d · Sub-Neptune Kepler-114 c · Super-Earth

Host System: Kepler-102

Spectral Class

K-type orange

Effective Temperature

4,909 K — cooler than the Sun (5,778 K)

Estimated Age

1.10 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.724 R☉

Stellar Mass

0.803 M☉

Metallicity [Fe/H]

0.11

Extended Stellar Properties

Surface gravity (log g)

4.600 dex

Stellar density

2.020 g/cm³

Systemic radial velocity

-27.67 km/s

Rotational v·sin i

0.50 km/s

Rotation period

27.95 days

Metallicity ratio

[Fe/H]

Distance

107.80 parsec

Light-years 351.58 ly

V-band magnitude

12.07 mag

Voyager-speed travel 6,200,168 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

9.248 mas

Total Proper Motion

59.615 mas/yr

PM Right Ascension

-41.14 mas/yr

PM Declination

-43.14 mas/yr

Galactic Cartesian (pc)

x = 0.135 · y = -0.666 · z = 0.734

Equatorial (J2000)

RA 281.48247° · Dec 47.20783°

Galactic ℓ, b

76.484° · 20.435°

Ecliptic λ, β

292.976° · 69.733°

HTM-20 index

1736978485

Similar Worlds

Kepler-1009 b

Sub-Neptune · K-type orange

Radius 2.17 R⊕ · 1,157.9 ly

Kepler-1329 b

Sub-Neptune · K-type orange

Radius 2.17 R⊕ · 1,917.9 ly

Kepler-304 c

Sub-Neptune · K-type orange

Radius 2.17 R⊕ · 1,417.7 ly

HD 20781 c

Sub-Neptune · K-type orange

Radius 2.17 R⊕ · 117.3 ly

Kepler-1653 b

Sub-Neptune · K-type orange

Radius 2.17 R⊕ · 2,462.5 ly

TOI-904 c

Sub-Neptune · K-type orange

Radius 2.17 R⊕ · 150.3 ly

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